Question

Which of the following pairs of hormones are not antagonistic to each other?
A. Relaxin-Inhibin
B. Parathormone-Calcitonin
C. Insulin-Glucagon
D. Aldosterone-Atrial natriuretic factor

Answer 1

Hint: Parathromone increases the blood calcium levels by increasing the release of calcium from bones and by decreasing reabsorption of calcium from the intestine. Calcitonin decreases the blood calcium levels and is released from the C cells of the thyroid glands. Insulin and glucagon have antagonistic action as the former decreases the blood glucose levels and the later increases it. Aldosterone inhibits the secretion of the Atrial-natriuretic factor and shows biological antagonism.

Complete answer:
Relaxin is a hormone produced from the corpus luteum of the ovary and plays an important role in pregnancy in females. In males, it is present in semen and is secreted from the prostate gland.
During the 14th day of ovulation, the relaxin levels increase rapidly and in the absence of pregnancy, the levels of relaxin decline and menstruation occur.
It plays an important role in individualization, working in combination with steroid hormones, which prepares the endometrial layer for implantation.
The granulosa cells in the ovaries secrete inhibin hormone which plays a role in inhibiting the secretion of the follicle-stimulating hormone by the anterior pituitary gland.

Hence, the correct option is (A) Relaxin-Inhibin

Note: The Relaxin and inhibin work synergistically and show a potentiation effect in regulating the release of Follicle-stimulating hormone during pregnancy and even in normal females.